A multi-wheeled base for a mobile cart includes one or more swiveling, optionally locking, caster wheels and one or more non-swiveling traction wheels to improve the maneuverability of the cart by making it easier to steer and stop. The traction wheels may be manually-engaged traction wheels, which may be operated by a cam and lever. The traction wheels may also be automatically-engaged traction wheels operated by a motor and a threaded shaft, and activated by a motion-sensitive sensor or by an on/off electrical switch or button. The traction wheels are preferably in contact with the floor when the mobile cart is moving, and raised above the surface of the floor when the cart is stationary.